public NFA(string regexp)
{
var ops = new Stack <int>();
_regx = regexp.ToCharArray();
_states = _regx.Length;
_graph = new Digraph(_states + 1);
for (var i = 0; i < _states; i++)
{
var lp = i;
if (_regx[i] == '(' || _regx[i] == '|')
{
ops.Push(i);
}
else if (_regx[i] == ')')
{
var or = ops.Pop();
if (_regx[or] == '|')
{
lp = ops.Pop();
_graph.AddEdge(lp, or + 1);
_graph.AddEdge(or, i);
}
else
{
lp = or;
}
}
if (i < _states - 1 && _regx[i + 1] == '*')
{
_graph.AddEdge(lp, i + 1);
_graph.AddEdge(i + 1, lp);
}
if (_regx[i] == '(' || _regx[i] == '*' || _regx[i] == ')')
{
_graph.AddEdge(i, i + 1);
}
}
}
public NFA(string regexp)
{
Stack <int> ops = new Stack <int>();
_re = regexp.ToCharArray();
M = _re.Length;
G = new Digraph(M + 1);
for (int i = 0; i < M; i++)
{
int lp = i;
if (_re[i] == '(' || _re[i] == '|')
{
ops.Push(i);
}
else if (_re[i] == ')')
{
int or = ops.Pop();
if (_re[or] == '|')
{
lp = ops.Pop();
G.AddEdge(lp, or + 1);
G.AddEdge(or, i);
}
else
{
lp = or;
}
}
if (i < M - 1 && _re[i + 1] == '*')
{
G.AddEdge(lp, i + 1);
G.AddEdge(i + 1, lp);
}
if (_re[i] == '(' || _re[i] == '*' || _re[i] == ')')
{
G.AddEdge(i, i + 1);
}
}
}
public Digraph Reverse()
{
Digraph d = new Digraph(_vertices);
for (int v = 0; v < _adjs.Length; v++)
{
foreach (int w in _adjs[v])
{
d.AddEdge(w, v);
}
}
return(d);
}
public Digraph Reverse(int v)
{
var graph = new Digraph(v);
for (var i = 0; i < _vertices; i++)
{
foreach (var w in _adj[v])
{
graph.AddEdge(w, v);
}
}
return(graph);
}